One method of construction for heat exchangers that is frequently employed (for example, in radiators for internal combustion engines) relies upon a heat exchange core comprised of multiple parallel flattened tubes interleaved with and bonded to corrugated fin structures. Such heat exchangers function by transferring heat between a first fluid (engine coolant, for example) traveling through the tubes and a second fluid (air, for example) passing over the tubes through the corrugated fin structures.
In order to prevent leakage of the first fluid as it passes through such a heat exchanger, the tubes are typically fastened to a header plate at either end, and the header plates are in turn each fastened to a tank. The first fluid enters one of the tanks (the inlet tank) through an inlet port, and exits one of the tanks (the outlet tank) through an outlet port. The inlet tank thus serves as a fluid manifold to distribute the fluid from the inlet port to the tubes.
In order to optimize the heat transfer performance of the heat exchanger, it is highly desirable for the first fluid to distribute evenly between the multiple tubes. In many cases the design of the inlet tank and its inlet port is specifically directed towards producing as uniform a flow distribution between the tubes as possible. However, in many applications this can be made difficult by restrictions imposed upon the heat exchanger by other parts of the system. In some applications, the inlet port may need to be located in an area of the inlet tank that makes uniform distribution of the fluid difficult to achieve. In some applications the available space for fluid lines may be so limited as to require a line size that results in the fluid entering the inlet tank at a high velocity, also making uniform distribution of the fluid difficult to achieve.
When the inlet port is oriented in a direction that is parallel to the axial direction of the tubes, the flow distribution in the tubes may be improved by the addition of a baffle plate located within the inlet tank so that the flow entering the tank through the inlet port impinges thereon. The impingement of the flow upon the baffle plate prevents the fluid from flowing disproportionately through the tubes immediately adjacent the inlet port. Such a solution to the problem of flow distribution in heat exchangers of this type is described in greater detail in U.S. Pat. No. 5,186,249.
The inventors have found that a baffle such as described above does not adequately prevent flow maldistribution through the heat exchanger tubes when the inlet port is instead oriented in a direction perpendicular to the axial direction of the tubes. This has been found to be especially true in cases where the flow area of the inlet port is sufficiently small relative to the fluid flow rate so that the fluid enters the inlet tank in a turbulent flow regime. Thus, there is still room for improvement.